xr400 blown engine

[gav03]

Out on my XR400 last night, engine suddenly stopped. Unable to restart and seems that there is no compression on the kick start.

As this engine has had a big bore 440 conversion sometime in its past life, is it worth rebuilding or is it easier/cheaper just to replace with a second hand engine?

Where would I source an engine, or where is the best place to take the damaged engine for rebuild/repair?

Any advice/ideas much appreciated.

Gav

[phil w]

Has been asked before, and Jason BC will give you good reasons why the 440 is troublesome. Sourcing an engine is not easy sometimes come up but means lots of phone calls and do you know what condition they are in.
The engine is better to be re built, I had mine done at a cost of £500 and its running fine for last 3000 kms.
The guy who rebuilt mine, sold a 400 engine on e bay that had the same rebuild as mine and it sold for £800
Food for thought

[catteeclan]

Got to see where the compression's going first.

[jasonbc]

Originally Posted by gav03

Out on my XR400 last night, engine suddenly stopped. Unable to restart and seems that there is no compression on the kick start.

As this engine has had a big bore 440 conversion sometime in its past life, is it worth rebuilding or is it easier/cheaper just to replace with a second hand engine?

Where would I source an engine, or where is the best place to take the damaged engine for rebuild/repair?

Any advice/ideas much appreciated.

Gav

Rebuild it as a standard 400 and then leave it alone, don't bother trying to find a secondhand one, you don't know what the internals on that will be like. I bought all my bits from david silver on the 3 week wait (because it's cheaper), cylinder with liner, piston ,rings, complete gaskets, valve seals, gudgeon pin,and probably alot more. Only thing i didn't buy was the conrod because honda will only supply a complete crank assembly at £580. I got a HOtrods conrod from offroad only and then got it pressed onto the crank and the bearings then wired.













That was the result of metal fatigue in the conrod and the over revving of the 440, it had the weisco 12.5:1 high compression kit, drilled air box and jetted to around 185. Put you photo's up later and we'll compare damage to see how similar it is. I think the only reason these 440 kits get fitted is because it cheaper to press an new liner in or bore the old one out and then fit a bit bigger piston. Either way they are a pain in the arse. Ca't remeber how much the parts cost without finding the bill but it was around £430 and £85 for the conrod to be pressed trued and wired, not a job i could do at home. It had 15 hours on the spark eroder trying to put a hole in the crank pin as it had heat treated itself and would collapse to allow it to be pressed out

[walesxr]

Originally Posted by gav03

Out on my XR400 last night, engine suddenly stopped. Unable to restart and seems that there is no compression on the kick start.

As this engine has had a big bore 440 conversion sometime in its past life, is it worth rebuilding or is it easier/cheaper just to replace with a second hand engine?

Where would I source an engine, or where is the best place to take the damaged engine for rebuild/repair?

Any advice/ideas much appreciated.

Gav

Could be a number of different reasons for this, some cheaper than others. But it has got to be worth removing engine top-end to see what has failed, then you can source some secondhand or new items to rebuild engine. As there is still plenty of spares kicking around for these engines. But as already mentioned buying a secondhand engine can be very costly and you don't really know what you are getting.

[gav03]

Thanks for the replies.

Looks like a rebuild is the way forward. Who would you recommend to carry out the work - I don't have the time to do it myself.

Gav

[walesxr]

Originally Posted by gav03

Thanks for the replies.

Looks like a rebuild is the way forward. Who would you recommend to carry out the work - I don't have the time to do it myself.

Gav

I don't know your area, so you will have to go on local recommendation, But do not start to take your engine apart unless you are able to rebuild it, as there is nothing worse than rebuilding a engine that someone else has taken apart and maybe lost some of the smaller items.

[Xman]

Its worth taking the head off first with the engine in the bike. You may have just a broken valve spring or something causing the engine to be losing compression and it could be a cheap easy fix.